It has been determined that cyclic performance of alkali battery cells are substantially affected by the purity of the electrolytes used in these cells. Therefore, it has been found necessary to devise effective procedures for eliminating or substantially reducing the impurities of these electrolytes. The impurities have been found in both the salt solutes of the electrolytes and also in their organic solvents. Sometimes, impurities will result upon mixing of the salt solute with the organic solvent irregardless of their purity.
It has been discovered that at least two types of impurity can be found in electrolytes: (a) those that react directly with the alkali metal anode and are reduced thereby: and (b) those that react with the cathode and are thereby oxidized. The product or products of this oxidation can then further react with the anode as in (a) above.
The invention discloses a method of inactivating or eliminating both types of impurities.